package com.qst.itoffer.servlet;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;

import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;


@SuppressWarnings("ALL")
@WebServlet("/ValidateCodeServlet")
public class ValidateCodeServlet extends HttpServlet {

    public ValidateCodeServlet() {
        super();
    }

    protected void doGet(HttpServletRequest request,
                         HttpServletResponse response) throws ServletException, IOException {
        // 设置响应头 Content-type类型
        response.setContentType("image/jpeg");
        // 获取二进制数据输出流对象
        ServletOutputStream out = response.getOutputStream();
        // 创建缓冲图象
        int width = 60;
        int height = 20;
        BufferedImage imgbuf = new BufferedImage(width, height,
                BufferedImage.TYPE_INT_RGB);
        Graphics2D g = imgbuf.createGraphics();
        // 设定背景色
        g.setColor(getRandColor(200, 250));
        // 设定图像形状及宽高
        g.fillRect(0, 0, width, height);
        // 随机产生100条干扰线，使图象中的认证码不易被其它程序探测到
        Random r = new Random();
        g.setColor(getRandColor(160, 200));
        for (int i = 0; i < 100; i++) {
            int x = r.nextInt(width);
            int y = r.nextInt(height);
            int xl = r.nextInt(12);
            int yl = r.nextInt(12);
            g.drawLine(x, y, x + xl, y + yl);
        }
        // 随机产生100个干扰点，使图像中的验证码不易被其他分析程序探测到
        g.setColor(getRandColor(120, 240));
        for (int i = 0; i < 100; i++) {
            int x = r.nextInt(width);
            int y = r.nextInt(height);
            g.drawOval(x, y, 0, 0);
        }
        // 随机产生0-9之间的4位数字验证码
        g.setFont(new Font("Times New Roman", Font.PLAIN, 18));
        String code = "";
        for (int i = 0; i < 4; i++) {
            String rand = String.valueOf(r.nextInt(10));
            code += rand;
            g.setColor(new Color(20 + r.nextInt(110), 20 + r.nextInt(110),
                    20 + r.nextInt(110)));
            g.drawString(rand, 13 * i + 6, 16);
        }
        // 将验证码保存到session中
        request.getSession().setAttribute("SESSION_VALIDATECODE", code);
        // 输出图像
        ImageIO.write(imgbuf, "JPEG", out);
        out.close();
    }

    protected void doPost(HttpServletRequest request,
                          HttpServletResponse response) throws ServletException, IOException {
    }

    // 获取指定范围的随机颜色
    private Color getRandColor(int fc, int bc) {
        Random random = new Random();
        if (fc > 255)
            fc = 255;
        if (fc < 0)
            fc = 0;
        if (bc > 255)
            bc = 255;
        if (bc < 0)
            bc = 0;
        int r = fc + random.nextInt(bc - fc);
        int g = fc + random.nextInt(bc - fc);
        int b = fc + random.nextInt(bc - fc);
        return new Color(r, g, b);
    }
}
